RAK811 and RAK811-N operating voltage

What is the operating voltage of the RAK811 and RAK811-N? In the datasheet I only can find the recommended operating voltage (3.15 to 3.45V). I would like to work with a primary lithium battery of 3.6V.
My question is: what is the minimum operating voltage (I hope close to 2.7V) and what is the maximum operating voltage?

Most LoRa modules work with an operating voltage between 2.1V and 3.6V. Are there any components used in the RAK811 (like the TCXO) which have a limited operational voltage?
A lot of LoRa applications are battery powered and using primary lithium of 3.6V. The power circuit can be kept simpler (saves costs) when the operational voltage of the LoRa module has a wider spec!